Application of Magnetic Field Sensors in Industrial and Medical Fields

Magnetic field sensors are composed of Hall effect and magnetoresistive semiconductor ICs, used to track angular velocity and linear angle in machines and products, or to detect and process magnetic fields to establish positional relationships. In industrial and medical applications, magnetic field sensors are used in motors to improve their efficiency. Magnetic sensor applications are also in a range of medical devices involving some form of motor control, such as pumps.

Industrial applications of magnetic field sensors are extensive

In industrial applications, renewable energy systems such as solar installations and wind turbines have always been the main growth points for magnetic field sensors. On the other hand, power consumption estimates for various types of motors account for 45% of the total, and if motor efficiency can be improved, a large amount of energy can be saved. Government legislation focuses on energy efficiency, which is also beneficial for sensors.

Examples of motors using a magnetic cylinder sensor include low-voltage AC and DC motors, three-phase induction motors, stepper motors, servo motors, single-phase motors, and compact motor drivers.

In other industrial applications, magnetic field sensors can be used in machines such as computer servers for uninterruptible power supplies (UPS), welding systems, robotics, train transportation infrastructure, off-road vehicles, and forklifts.

In the field of industrial applications, the most popular type of magnetic field sensor is the current sensor, including shunt resistors, Hall effect integrated circuits, current-inducing transformers, open-loop and closed-loop Hall devices, and magnetic flux gate sensors. In many applications measuring currents below 50 amperes, such as residential solar inverter applications or small UPS systems, simple resistance rods or shunts are used.

However, as the measured current intensity increases, shunting becomes cumbersome and expensive. In applications with higher current such as large variable frequency motors, open-loop and closed-loop Hall sensors use a Hall effect IC in a small package; they can also improve integration by including a dedicated integrated circuit in the package. Hall ICs are also used in industrial washing machine inverter control applications.

In addition to current sensors, there is also a smaller market for independent Hall effect ICs or magnetoresistive sensor switches, which are used for motor rectification to reduce ripple and improve performance, or for position measurement.

Magnetic field sensors play a critical role in medical applications

In the medical field, although the scale is smaller than in the industrial field, magnetic field sensors can save lives or improve quality of life. They are mainly used in medical devices using commutation sensors for motor control, such as applications in ventilators; infusion, insulin, and syringe pumps; or kidney dialysis machines.

Another example of sensor applications in the medical field is in simple centrifuges used for sample preparation. Sensors are used to help control small motors, making them quieter and more reliable.

The waterproof magnetic reed switch is also a prominent application, used in safe operating medicine cabinets, or bed adjustments and hearing aids. In the field of hearing aids, giant magnetoresistance sensors compete with Hall effect and reed switches.